The casting of media to media renderers (e.g., televisions, monitors, and music players) is becoming increasing popular. “Casting” refers to a technique in which a device (e.g., smartphone or tablet) discovers media renderers and then transmits (e.g., wirelessly) media to a discovered media renderer. In some cases, the device discovers media renderers that are part of the same network to which the device is connected by multicasting a discovery request through the network. In other cases, the device may discover media renderers based on proximity to the media renderers, for example, using Bluetooth technology. Many media renderers are casting-enabled or may be made casting-enabled by attaching a casting device to one of their inputs (e.g., the HDMI port of a television).
Casting can be used to transmit various types of media. For example, a tablet that is currently playing a video may cast that video to a media renderer such as a television. As another example, a smartphone that is being streamed music can cast the music to a music player, mobile speakers, a car, or possibly a television. As another example, a desktop computer can cast the content of its display or a window of the display to a media renderer.
The use of casting has simplified the sharing of media renderers. For example, many meeting rooms come equipped with audiovisual systems. Prior to casting, a person who wanted to display information on a media renderer in a meeting room would need to physically connect their device (e.g., laptop) to a cable connected to the media renderer. A meeting room may provide many different types of connectors (e.g., HDMI, USB, and RCA) and/or adapters to accommodate the different type of connectors supported by media renderers and devices. The switching from the connecting of the media renderer from one person's device to another person's device is often cumbersome because cables need to be physically disconnected and connected and the compatible connectors need to be identified.
Although casting has simplified the sharing of media renderers, it has the disadvantage that whenever a device casts media to a media renderer, the media is immediately rendered by the media renderer. For example, in a classroom setting, a teacher may direct a student to cast a presentation to a display in front of the classroom. If another student were inadvertently or intentionally to cast a video to the display, the video would immediately replace the presentation. As another example, someone in an adjacent classroom might cast their media to the display in the other classroom, thinking that the display was in their classroom.